Old World Trade Diasporas

What explains worldwide, historical patterns of trade diaspora dispersal? In the premodern period, trade diasporas were among the most important communities facilitating cross-cultural exchange over long distances. We argue that two general principles explain the proliferation of premodern trade diasporas. First, diaspora merchants were drawn to wealthy societies with the goal of obtaining access to high-value luxury goods produced through the development of complex supply chains. Second, traders sought to establish diaspora communities in locations that exhibited bioclimatic complementarities to the merchant's home region, thereby assisting the procurement of relatively uncommon natural resources. To empirically assess these arguments, we examine the historical record for information about the product composition of historical trade; collect data on the locations of trade diaspora communities across Eurasia between 600 and 1600 AD; and develop an agent-based model that specifies the agents' (i.e., traders') rule-based decisions to migrate in a wealth and resource-differentiated geographic space that represents Eurasia. Taken together, our findings describe the conditions that facilitated diaspora creation and historical cross-cultural exchange - a topic of rich exploration in the fields of global historical sociology and international political economy.